Short answers, pulled from the story.
The production budget for The Good, the Bad and the Ugly was approximately $1.2 million. United Artists advanced $500,000 upfront and agreed to take 50% of box-office receipts outside Italy. The film grossed over $38 million worldwide.
The Good, the Bad and the Ugly was filmed primarily in Spain, including the Tabernas Desert in Almería, the Arlanza River valley near Hortigüela, and the purpose-built Sad Hill Cemetery near Santo Domingo de Silos. Production began at Cinecittà Studios in Rome in mid-May 1966 before moving to Spain.
Ennio Morricone composed the score for The Good, the Bad and the Ugly. He and Leone developed the principal themes before filming began, and the soundtrack was released in 1968, reaching number four on the Billboard pop chart. A cover of the main theme by Hugo Montenegro reached number two on the Billboard Hot 100.
Clint Eastwood was paid $250,000 and received ten percent of profits from North American markets for his role as Blondie in The Good, the Bad and the Ugly. Leone negotiated the deal reluctantly and was not happy with the terms.
Eli Wallach faced three life-threatening incidents during filming. He accidentally drank from a bottle of acid, was carried nearly a mile on a runaway horse with his hands bound, and lay beside railroad tracks unaware that heavy iron steps jutted one foot out of every passing box car. Wallach wrote about these incidents in his autobiography and criticized Leone for being very lax about actor safety.
The Good, the Bad and the Ugly was released in Italy on the 23rd of December 1966, at a running time of 177 minutes. Leone later shortened it to 174 minutes by removing the "grotto" scene. United States prints ran 161 minutes, and some British prints ran as short as 148 minutes. The 2004 MGM special edition DVD restored the fourteen minutes cut from the North American release.